Method for treating an extracted tobacco pulp and tobacco products made therefrom

ABSTRACT

The invention provides a method of producing a tobacco composition for use in a tobacco product, the method including treating a tobacco pulp with supercritical carbon dioxide. The treated tobacco pulp may exhibit a benzo[a]pyrene concentration lower than the initial benzo[a]pyrene concentration and/or a TSNA concentration lower than the initial TSNA concentration. The treated pulp can be introduced into tobacco products including smoking articles, smokeless tobacco products, and aerosol-generating devices configured for non-combustion of plant materials.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. application Ser. No.12,949,361, filed Nov. 18, 2010, which is hereby incorporated byreference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates to products made or derived from tobacco,or that otherwise incorporate tobacco, and are intended for humanconsumption. In particular, the disclosure relates to compositions orformulations incorporating tobacco, such as those intended to beemployed in a smokeless form.

BACKGROUND OF THE INVENTION

Cigarettes, cigars, and pipes are popular smoking articles that employtobacco in various fauns. Such smoking articles are employed by heatingor burning tobacco to generate aerosol (e.g., smoke) that may be inhaledby the smoker. Tobacco may also be enjoyed in a so-called “smokeless”form. Particularly popular smokeless tobacco products are employed byinserting some form of processed tobacco or tobacco-containingformulation into the mouth of the user. See for example, the types ofsmokeless tobacco formulations, ingredients, and processingmethodologies set forth in U.S. Pat. Nos. 1,376,586 to Schwartz;3,696,917 to Levi; 4,513,756 to Pittman et al.; 4,528,993 to Sensabaugh,Jr. et al.; 4,624,269 to Story et al.; 4,991,599 to Tibbetts; 4,987,907to Townsend; 5,092,352 to Sprinkle, I I I et al.; 5,387,416 to White etal.; 6,668,839 to Williams; 6,834,654 to Williams; 6,953,040 to Atchleyet al.; 7,032,601 to Atchley et al.; and 7,694,686 to Breslin et al.; USPat. Pub. Nos. 2004/0020503 to Williams; 2005/0115580 to Quinter et al.;2005/0244521 to Strickland et al.; 2006/0191548 to Strickland et al.;2007/0062549 to Holton, Jr. et al.; 2007/0186941 to Holton, Jr. et al.;2007/0186942 to Strickland et al.; 2008/0029110 to Dube et al.;2008/0029116 to Robinson et al.; 2008/0029117 to Mua et al.;2008/0173317 to Robinson et al.; 2008/0196730 to Engstrom et al.;2008/0209586 to Neilsen et al.; 2008/0305216 to Crawford et al.;2009/0065013 to Essen et al.; and 2009/0293889 to Kumar et al.; PCT WO04/095959 to Arnarp et al.; and U.S. patent application Ser. No.12/638,394, filed Dec. 15, 2009, to Mua et al.; each of which isincorporated herein by reference.

One type of smokeless tobacco product is referred to as “snuff.”Representative types of moist snuff products, commonly referred to as“snus,” are manufactured in the United States and Europe, particularlyin Sweden. See, for example, Bryzgalov et al., 1N1800 Life CycleAssessment, Comparative Life Cycle Assessment of General Loose andPortion Snus (2005). In addition, certain quality standards associatedwith snus manufacture have been assembled as a so-called GothiaTekstandard. Exemplary smokeless tobacco products include CAMEL Snus, CAMELOrbs, CAMEL Strips and CAMEL Sticks by R. J. Reynolds Tobacco Company;REVEL Mint Tobacco Packs and SKOAL Snus by U.S. Smokeless TobaccoCompany; and MARLBORO Snus and Taboka by Philip Morris USA.

Various treatment methods and additives have been proposed for alteringthe overall character or nature of tobacco materials utilized in tobaccoproducts. For example, additives or treatment processes have beenutilized in order to alter the chemistry or sensory properties of thetobacco material, or in the case of smokable tobacco materials, to alterthe chemistry or sensory properties of mainstream smoke generated bysmoking articles including the tobacco material. See, for example,Leffingwell et al., Tobacco Flavoring for Smoking Products, R.J.Reynolds Tobacco Company (1972), which is incorporated herein byreference. In addition, tobacco materials have been processed or blendedin a manner designed to achieve certain sensory or chemistrycharacteristics. See, for example, U.S. Pat. No. 7,025,066 to Lawson etal. and US Pat. Pub. No. 2008/0245377 to Marshall et al., which areincorporated herein by reference.

It would be desirable to provide an enjoyable form of tobacco product,such as a smokeless tobacco product, and to provide processes forpreparing tobacco-containing compositions suitable for use in smokelesstobacco products.

SUMMARY OF THE INVENTION

The present invention relates to a tobacco product, such as a smokelesstobacco product (e.g., moist snuff, dry snuff, chewing tobacco,tobacco-containing gums, and dissolvable or meltable tobacco products)intended or configured for insertion into the mouth of a user, and toprocesses for preparing a formulation suitable for use within such atobacco product. The tobacco products of the invention include aflavorful tobacco composition such as one having the form of afire-cured tobacco extract. In one embodiment, the invention providesfire-cured tobacco extracts that exhibit distinctive sensorycharacteristics associated with fire-cured tobacco (e.g., smoky aroma orflavor), while also exhibiting advantageous chemical compositiondifferences as compared to fire-cured tobacco in whole form, such asreduced levels of benzo[a]pyrene or other polycyclic aromatichydrocarbons.

The extract is typically an aqueous extract of the cured tobaccomaterial, but certain other polar protic solvents or co-solvent mixturesthat include water can be used without departing from the invention. Theconcentration of benzo[a]pyrene in the extract is typically no more thanabout 10 ppb and often no more than about 5 ppb.

Although smokeless tobacco composition are particularly important typesof tobacco products that would benefit from the extracts of theinvention, other tobacco products can also benefit from such flavorfultobacco compositions, such as smoking articles (e.g., cigarettes) oraerosol-generating devices that contain tobacco or tobacco componentsbut which do not combust tobacco or other plant material. Typically, thetobacco product will comprise a tobacco material or a non-tobacco plantmaterial as a carrier for the extract.

In another embodiment, the extract of the invention is used to form areconstituted tobacco material. In particular, such a material caninclude the extract of the invention (e.g., a fire-cured tobaccoextract) combined with an extracted tobacco pulp (e.g., a fire-curedtobacco pulp), wherein the pulp has been pre-treated to reducebenzo[a]pyrene concentration. For example, the fire-cured tobaccoextracted pulp can be pre-treated by supercritical carbon dioxideextraction to reduce benzo[a]pyrene concentration.

In another aspect, the invention provides a method of producing aflavorful tobacco composition characterized by sensory attributesassociated with a fire-cured tobacco material and a reducedbenzo[a]pyrene concentration. The method includes the step of mixing afire-cured tobacco material having a first benzo[a]pyrene concentration(e.g., at least about 100 ppb benzo[a]pyrene) with a polar proticsolvent (e.g., water or co-solvent mixtures including water) to producea slurry, the slurry providing intimate contact between the fire-curedtobacco material and the polar protic solvent. The method also includesmaintaining the slurry for a time and at a temperature sufficient toform an extract comprising components of the cured tobacco materialsoluble in the polar protic solvent, the extract exhibiting a secondbenzo[a]pyrene concentration (e.g., less than about 10 ppbbenzo[a]pyrene) lower than the first benzo[a]pyrene concentration.Thereafter, the extract is separated from a residual pulp materialcomprising components of the fire-cured tobacco material that areinsoluble in the polar protic solvent. The method typically alsoincludes the step of utilizing the extract as a flavorful tobaccocomposition by, for example, introducing the separated extract into atobacco product, which will often involve applying the separated extractto a tobacco material or non-tobacco plant material to form a treatedmaterial that can then be incorporated into a tobacco product. Incertain embodiments, the extract is recombined with the extracted pulpfollowing treatment of the pulp to reduce benzo[a]pyrene content, suchas a second extraction of the pulp adapted to remove benzo[a]pyrene. Forexample, the method can include treating the residual pulp material withsupercritical carbon dioxide to reduce benzo[a]pyrene concentration andform a pulp material with reduced benzo[a]pyrene concentration, andthereafter applying the separated extract to the pulp material withreduced benzo[a]pyrene concentration to form the treated material. Ifdesired, the extract can be concentrated by removing at least a portionof the solvent prior to incorporation into a tobacco product.

In one particular embodiment, the invention provides a process forpreparing a composition suitable for use as a smokeless tobaccocomposition, comprising: mixing a fire-cured tobacco material having afirst benzo[a]pyrene concentration with water to produce an aqueousslurry, the slurry providing intimate contact between the fire-curedtobacco material and the water; maintaining the slurry for a time and ata temperature sufficient to form a fire-cured tobacco extract comprisingflavorful and aromatic components of the fire-cured tobacco materialsoluble in water, the aqueous fire-cured tobacco extract exhibiting asecond benzo[a]pyrene concentration lower than the first benzo[a]pyreneconcentration; separating the aqueous fire-cured tobacco extract from aresidual pulp material comprising components of the fire-cured tobaccomaterial that are insoluble in water; and mixing the aqueous fire-curedtobacco extract with a tobacco or non-tobacco plant material to form asmokeless tobacco composition.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to provide an understanding of embodiments of the invention,reference is made to the appended drawings, which are not necessarilydrawn to scale, and in which reference numerals refer to components ofexemplary embodiments of the invention. The drawings are exemplary only,and should not be construed as limiting the invention.

FIG. 1 is an exploded perspective view of a smoking article having theform of a cigarette, showing the smokable material, the wrappingmaterial components, and the filter element of the cigarette; and

FIG. 2 is a cross-sectional view of a smokeless tobacco productembodiment, taken across the width of the product, showing an outerpouch filled with a smokeless tobacco composition of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention now will be described more fully hereinafter. Thisinvention may, however, be embodied in many different forms and shouldnot be construed as limited to the embodiments set forth herein; rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the invention to thoseskilled in the art. As used in this specification and the claims, thesingular forms “a,” “an,” and “the” include plural referents unless thecontext clearly dictates otherwise. Reference to “dry weight percent” or“dry weight basis” refers to weight on the basis of dry ingredients(i.e., all ingredients except water).

The present invention provides a process for preparing a flavorfultobacco composition it the form of a tobacco extract. In certainembodiments, the extracts of the invention provide a tobacco compositionhaving advantageous sensory characteristics combined with a reducedamount of certain compounds found in the unextracted tobacco material.The process of the invention is particularly useful for forming anextract of a fire-cured tobacco material, although it can be applied toother tobacco materials such as tobacco cured using other curingtechniques (e.g., air-cured and/or flue-cured tobacco materials). See,for example, techniques for curing tobacco set forth in US Pat. App.Pub. No. 2012/0037175 to Cantrell et al. and selected references citedtherein, which are incorporated by reference in their entireties.

A “fire-cured tobacco” as used herein refers to a tobacco materialsubjected to a fire curing process. In fire curing, tobacco leaves areexposed to gaseous combustion products from an open fire in the curingenclosure, typically for several weeks, resulting in a distinctive smokyaroma and flavor. The distinctive sensory characteristics of fire-curedtobacco can also be described in some cases as woody, sweet, nutty,spicy, earthy, or sour. The fire used for such curing processes istypically characterized as low-burning or smoldering, meaning the fireis maintained in a state that promotes smoke production. Fire curedtobaccos are sometimes referred to as “dark fire” or “dark-fired”tobacco. See, for example, the fire-curing processes and resultingtobacco characteristics set forth in U.S. Pat. Nos. 7,650,891 and7,650,892, both to Groves et al., and 7,757,697 to Thomas et al., all ofwhich are incorporated by reference herein. See also, pages 164-182 ofTobacco Production, Chemistry and Technology, Davis et al. (Eds.)(1999).

During fire curing, the tobacco material is involved in intimateinteraction and contact with the gaseous combustion products of the firein the curing enclosure, meaning the smoke from the fire directlycontacts the surface of the tobacco material. This interaction betweenthe smoke and the tobacco results in chemical changes to the tobaccomaterial that lead to both the distinctive smoky aroma and flavorcommonly associated with fire-cured tobacco and other less desirablechemical changes in the tobacco. The present invention provides atreatment process that separates at least a portion of the components ofthe fire-cured tobacco that provide the distinctive sensorycharacteristics (i.e., smoky aroma and flavor) from at least a portionof the components of the fire-cured tobacco that do not contribute to asignificant degree to the desired and distinctive sensorycharacteristics. In other words, the invention provides a separationprocess that selectively extracts components of fire-cured tobacco thatare desirable from a sensory standpoint, but leaves behind at least aportion of those components that are not necessary or desirable from asensory standpoint.

When the process of the invention is applied to a fire-cured tobaccomaterial, an extract can be formed in certain embodiments that ischaracterized by the desirable sensory attributes (e.g., smoky aroma andflavor) associated with fire-cured tobacco, but with an alteredchemistry profile that includes reduction in certain polycyclic aromatichydrocarbons typically found in fire-cured tobacco, such asbenzo[a]pyrene (i.e., BaP or B[a]p). The structure of BaP is givenbelow.

Discussion of BaP and other polycyclic aromatic hydrocarbons can befound in Gelboin, Physiological Reviews 60(4) (1980) 1107-1166;Phillips, Mutation Research 443 (1999) 139-147; Rodgman and Perfetti,Contributions to Tobacco Research 22(1) (2006) 13-69; Rodgman and Cook,Contributions to Tobacco Research 23(6) (2009) 384-410; and A. Rodgmanand T. A. Perfetti, The Chemical Components of Tobacco and TobaccoSmoke, CRC Press, Taylor and Francis Group, Boca Raton, USA, (2009), allof which are incorporated by reference herein.

Fire-cured tobacco extracts containing reduced levels of polycyclicaromatic hydrocarbons enable the production of smoking articles andsmokeless tobacco compositions that exhibit the desirable sensorycharacteristics of fire-cured tobacco, but with reduced content ofcompounds not associated with the desirable sensory properties, such asBaP. It is noted that sensory characteristics of a composition can beevaluated using human sensory panels as is understood in the art.Although the BaP content can vary based on the particular tobacco plantand specific fire-curing process employed, a typical BaP range for afire-cured tobacco is about 150 to about 800 parts by billion (ppb). Incertain embodiments of the invention, fire-cured tobacco extracts can beformed with significantly lower BaP levels, such as less than about 10ppb, less than about 5 ppb, or even less than about 1 ppb. In otherterms, the amount of BaP reduction that occurs during the extractionprocess of the invention can be characterized as a reduction of at leastabout 90 percent by weight of the content of BaP in the originalunextracted tobacco material, more often at least about 95 percent or atleast about 99 percent. It was heretofore unknown that a fire-curedtobacco extract could be formed that retains the distinctive sensoryelements of such tobaccos, but which exhibits a reduced content ofcertain less desirable chemical compounds such as BaP. In one embodimentof the method of the invention, the cured tobacco material (e.g.,fire-cured tobacco) subjected to the extraction process has a BaPconcentration of at least about 100 ppb, more often at least about 150ppb, or even at least about 200 ppb or at least about 300 ppb. Followingthe extraction process, the separated extract exhibits a much lower BaPconcentration, such as a concentration of no more than about 10 ppb, orno more than about 5 ppb, or no more than about 1 ppb.

Various methods for determining BaP content are known in the art.Typically, the method involves extracting BaP from a tobacco materialwith methanol or a relatively non-polar solvent such as hexane,cyclohexane or methylene chloride. The extract is then filtered andanalyzed using a High Performance Liquid Chromatography (HPLC) methodwith fluorescence detection or a Gas Chromatography-Mass Spectrometry(GC-MS) technique. Publications directed to extraction and detection ofBaP in tobacco or tobacco products include Rodgman and Perfetti,Contributions to Tobacco Research 22(1) (2006) 13-69; Risner, Beitr.Tabakforsch. Int 15(1) (1991) 11-17; “Determination of Benzo[a]Pyrene inWhole Tobacco,” Health Canada (1999) (published on the Health Canadawebsite, www.hc-sc.gc.ca), Aygün et al., International Journal of FoodSciences and Nutrition 56(8) (2005) 581-585; and McNeill et al., Tob.Control 15 (2006) 64-67, all of which are incorporated by referenceherein.

The fire-cured tobacco used in the process of the invention can includethose tobacco materials commonly utilized in fire curing, such as NarrowLeaf Madole, Improved Madole, Tom Rosson Madole, Newton's VH Madole,Little Crittenden, Green Wood, Little Wood, Small Stalk Black Mammoth,DT 508, DT 518, DT 592, KY 171, DF 911, DF 485, TN D94, TN D950, VA 309,and VA 359. However, any tobacco material could be used withoutdeparting from the invention, including those tobaccos commonly referredto as flue-cured or Virginia (e.g., K326), burley, sun-cured (e.g.,Indian Kurnool and Oriental tobaccos, including Katerini, Prelip,Komotini, Xanthi and Yambol tobaccos), Maryland, dark, dark air cured(e.g., Passanda, Cubano, Jatin and Bezuki tobaccos), light air cured(e.g., North Wisconsin and Galpao tobaccos), Indian air cured, RedRussian and Rustica tobaccos, as well as various other rare or specialtytobaccos. Descriptions of various types of tobaccos, growing practicesand harvesting practices are set forth in Tobacco Production, Chemistryand Technology, Davis et al. (Eds.) (1999), which is incorporated hereinby reference. Various representative types of plants from the Nicotianaspecies are set forth in Goodspeed, The Genus Nicotiana, (ChonicaBotanica) (1954); U.S. Pat. Nos. 4,660,577 to Sensabaugh, Jr. et al.;5,387,416 to White et al. and 7,025,066 to Lawson et al.; US PatentAppl. Pub. Nos. 2006/0037623 to Lawrence, Jr. and 2008/0245377 toMarshall et al.; each of which is incorporated herein by reference. Inone embodiment, tobacco varieties that are typically cured throughcuring processes other than fire curing, such as flue-curing orair-curing, are utilized in the extraction process of the invention. Ifdesired, such tobacco materials can be optionally cured using a firecuring treatment instead of the traditional curing process used for suchmaterials.

The particular Nicotiana species of material used in the invention couldalso vary. Of particular interest are N. alata, N. arentsii, N.excelsior, N. forgetiana, N. glauca, N. glutinosa, N. gossei, N.kawakamii, N. knightiana, N. langsdorffi, N. otophora, N. setchelli, N.sylvestris, N. tomentosa, N. tomentosifothiis, N. undulata, and N. xsanderae. Also of interest are N. africana, N. amplexicaulis, N.benavidesii, N. bonariensis, N. debneyi, N. longiflora, N. maritina, N.megalosiphon, N. occidentalis, N. paniculata, N. plumbaginifolia, N.raimondii, N. rosulata, N. rustica, N. simulans, N. stocktonii, N.suaveolens, N. tabacum, N. umbratica, N. velutina, and N. wigandioides.

Other plants from the Nicotiana species include N. acaulis, N.acuminata, N. attenuata, N. benthamiana, N. cavicola, N. clevelandii, N.cordifolia, N. corymbosa, N. fragrans, N. goodspeedii, N. linearis, N.miersii, N. nudicaulis, N. obtusifolia, N. occidentalis subsp.Hersperis, N. pauciflora, N. petunioides, N. quadrivalvis, N. repanda,N. rotundifolia, N. solanifolia and N. spegazzinii. The Nicotianaspecies can be derived using genetic-modification or crossbreedingtechniques (e.g., tobacco plants can be genetically engineered orcrossbred to increase or decrease production of certain components or tootherwise change certain characteristics or attributes). See, forexample, the types of genetic modifications of plants set forth in U.S.Pat. Nos. 5,539,093 to Fitzmaurice et al.; 5,668,295 to Wahab et al.;5,705,624 to Fitzmaurice et al.; 5,844,119 to Weigl; 6,730,832 toDominguez et al.; 7,173,170 to Liu et al.; 7,208,659 to Colliver et al.;and 7,230,160 to Benning et al.; US Patent Appl. Pub. No. 2006/0236434to Conkling et al.; and PCT WO 2008/103935 to Nielsen et al.

At least a portion of the plant of the Nicotiana species can be employedin an immature form (i.e., the plant, or at least one portion of thatplant, can be harvested before reaching a stage normally regarded asripe or mature, such as, for example, when the tobacco plant is at thepoint of a sprout, is commencing leaf formation, is commencingflowering, or the like). At least a portion of the plant can be employedin a mature form (i.e., the plant, or at least one portion of the plantcan be harvested when that plant (or plant portion) reaches a point thatis traditionally viewed as being ripe, over-ripe, or mature). As such,for example, through the use of tobacco harvesting techniquesconventionally employed by farmers, Oriental tobacco plants can beharvested, burley tobacco plants can be harvested, or Virginia tobaccoleaves can be harvested or primed by stalk position. The tobaccomaterial used in the invention can also be subjected to agingconditions.

The plant can, in certain embodiments, be used in a green form (e.g.,tobacco can be used without being subjected to any curing process). Forexample, tobacco in green form can be frozen, subjected to irradiation,yellowed, dried, cooked (e.g., roasted, fried or boiled), or otherwisesubjected to storage or treatment for later use. Such tobaccos can alsocan be subjected to aging conditions.

According to the invention, a tobacco material of any of the types notedabove is harvested and subjected to a curing process, such as a firecuring process. The resulting cured tobacco is then subjected to anextraction process using certain polar protic solvents, such as water,formic acid, acetic acid, dilute aqueous solutions (e.g., solutionscomprising greater than 70 weight percent water and minor amounts of analcohol or other co-solvent), or mixtures thereof. The solvent typicallyhas a dielectric constant at room temperature of at least about 6, moreoften at least about 30, and most often at least about 50.

Solvents having an aqueous character are particularly useful, such asdeionized water, distilled water, or tap water. Such a solvent consistsprimarily of water, is normally greater than 90 weight percent water,and can be essentially pure water in certain circumstances. Theextraction solvent can be a co-solvent mixture, such as a mixture ofwater and minor amounts of one or more solvents that are miscibletherewith. An example of such a co-solvent mixture is a solventconsisting of about 95 weight parts water and about 5 weight partsethanol. The extraction solvent also can include water having substancessuch as pH adjusters (i.e., acids or bases) or pH buffers dissolvedtherein.

The extraction process involves placing the tobacco material in intimatecontact with the solvent at a suitable temperature and for a suitabletime period. The temperature of the extraction can vary, but a typicaltemperature range is about room temperature to about 110° C., more oftenabout 30° C. to about 90° C. In certain embodiments, the temperature ofthe extraction step can be characterized as at least about 20° C., atleast about 30° C., at least about 50° C., or at least about 60° C. Itmay be advisable to use a relatively low temperature for the extractionprocess to prevent or reduce volatilization of the flavorful or aromaticcompounds that are the primary targets of the extraction process. Thetime period for the extraction step can vary, but is typically about 10minutes to about 24 hours, more often about 1 hour to about 12 hours.The time period is not considered particularly critical to theinvention, although very short extraction time periods may not result inextraction of a large proportion of the extractable component of thetobacco material.

The amount of solvent used in the extraction process can vary, but willtypically be sufficient to place the tobacco material in the form of aslurry. In other words, the solvent is typically the predominatecomponent of the tobacco/solvent mixture and is often present in greatexcess compared to the tobacco component. Weight ratios of solvent totobacco material will typically range from about 2:1 to about 20:1(e.g., about 4:1 to about 12:1), although other ratios (particularlyeven larger ratios) could be used without departing from the invention.In certain embodiments, the use of smaller amounts of water or othersolvent could be advantageous because less drying would be required ifthe extract must be concentrated prior to use. Excessive drying of theextract could lead to loss of certain volatile flavorful or aromaticcomponents of the extract, which could potentially result in loss ofsome of the distinctive sensory characteristics of the extract.Accordingly, use of weight ratios of solvent to tobacco material of lessthan about 5:1 or less than about 4:1 during extraction could be auseful technique to reduce or eliminate the need to dry or otherwiseconcentrate the resulting extract. In such an embodiment, the extractwould be expected to exhibit a relatively high viscosity and can beapplied to certain tobacco products without further processing.

The manner by which the solvent and the tobacco material are combinedfor extraction may vary. The solvent and tobacco material can becontacted, combined, or mixed together in conical-type blenders, mixingdrums, ribbon blenders, or the like. The mixture can be agitated orsubjected to a grinding action during the extraction step. Followingextraction, the residual pulp is removed from the liquid extractionproduct using any method known in the art, such as filtration orcentrifugation. The tobacco material is typically in shredded orparticulate form during extraction, such as tobacco particles having aparticle size in the range of about 0.5 mm to about 25 mm. The vessel inwhich the tobacco material and the solvent are mixed is typically ventedsuch that the extraction proceeds at atmospheric pressure, or ifdesired, a pressurized vessel can be used. Following the extractionprocess, a tobacco extract is provided by separating thesolvent-insoluble pulp material from the solvent and the solvent-solubleor dispersible tobacco components dissolved or dispersed therein.

Equipment, types of solvents, and techniques for obtaining extracts oftobacco, including in some cases equipment, solvents, and techniquesthat can be used or suitably modified for use in the method of theinvention, are described in U.S. Pat. Nos. 4,144,895 to Fiore; 4,150,677to Osborne, Jr. et al.; 4,267,847 to Reid; 4,289,147 to Wildman et al.;4,351,346 to Brummer et al.; 4,359,059 to Brummer et al.; 4,506,682 toMuller; 4,589,428 to Keritsis; 4,605,016 to Soga et al.; 4,716,911 toPoulose et al.; 4,727,889 to Niven, Jr. et al.; 4,887,618 to Bernasek etal.; 4,941,484 to Clapp et al.; 4,967,771 to Fagg et al.; 4,986,286 toRoberts et al.; 5,005,593 to Fagg et al.; 5,018,540 to Grubbs et al.;5,060,669 to White et al.; 5,065,775 to Fagg; 5,074,319 to White et al.;5,099,862 to White et al.; 5,121,757 to White et al.; 5,131,414 to Fagg;5,131,415 to Munoz et al.; 5,148,819 to Fagg; 5,197,494 to Kramer;5,230,354 to Smith et al.; 5,234,008 to Fagg; 5,243,999 to Smith;5,301,694 to Raymond et al.; 5,318,050 to Gonzalez-Parra et al.;5,343,879 to Teague; 5,360,022 to Newton; 5,435,325 to Clapp et al.;5,445,169 to Brinkley et al.; 6,131,584 to Lauterbach; 6,298,859 toKierulff et al.; 6,772,767 to Mua et al.; and 7,337,782 to Thompson, allof which are incorporated by reference herein.

Following separation of the extract from the pulp, both the extract andthe residual pulp can be further processed if desired. For example, theextract can be processed in a manner adapted to concentrate thedissolved or dispersed components of the tobacco material by removing atleast a portion of the solvent. Various methods of solvent removal canbe used, such as heat treatment to evaporate the solvent (e.g., with anevaporator and condenser arrangement), reverse osmosis membranetreatment, spray drying or freeze drying. In the case of an aqueousextract, the concentration step could simply entail heating the extractto a temperature above the boiling point of water in a vented vessel.The extract could also be subjected to other treatment processesdesigned to change the chemical composition of the extract, such asreaction with acids or bases, ultrafiltration to remove high molecularweight components, treatment to remove additional components of theextract such as tobacco-specific nitrosamines (TSNAs), or the like.

In one specific embodiment, the essentially BaP-free extract isprocessed to reduce the concentration of TSNAs in the extract. ExemplaryTSNA compounds include N-nitrosonornicotine (NNN),4-methyl-N-nitrosamino-1-(3-pyridyl)-1-butanone (NNK),N-nitrosoanatabine (NAT), 4-methyl-N-nitrosamino-1-(3-pyridyl)-1-butanol(NNAL), and N-nitrosoanabasine (NAB). The method for reducing the TSNAlevel can vary. In one method, a preparative HPLC technique is usedwhere the extract is passed through a HPLC column and the portion of theextract eluting from the column at the known retention time for TSNAcompounds is simply discarded. In another method, the extract is passedthrough a molecularly imprinted polymer (MIP) material having functionalgroups that selectively sorb TSNA compounds. Exemplary TSNA-specific MIPmaterials include polymer sorbents offered by Sigma-Aldrich Companyunder the brand name SupelMIP® SPE and Affinilute™ MIP materialsavailable from Biotage AB. The polymeric sorbent can be contacted withthe extract to selectively sorb the TSNA compounds using a variety oftechniques such as packing a column with the sorbent and passing theextract therethrough. In certain embodiments, the TSNA level of theextract can be reduced from greater than 1,000 ppb or even greater than2,000 ppb to less than about 400 ppb or less than about 300 ppb or lessthan about 200 ppb. In some cases, the TSNA level can be reduced to lessthan about 100 ppb or less than about 50 ppb.

In one embodiment, the residual tobacco pulp produced in the extractionprocess can be treated to reduce benzo[a]pyrene concentration in orderto prepare the pulp for recombination with the extract to form areconstituted tobacco material exhibiting a reduced benzo[a]pyreneconcentration. For example, the pulp could be subjected to a secondextraction process using supercritical carbon dioxide or anothersuitable solvent (e.g., relatively non-polar solvents such as hexane,cyclohexane or methylene chloride) such that the benzo[a]pyrenedissolves in the solvent to facilitate removal from the pulp. Carbondioxide extraction processes that could be used in the presentinvention, or suitably modified for use in the present invention, areset forth in, for example, U.S. Pat. Nos. 4,153,063 to Roselius et al.;4,506,682 to Muller; 4,714,617 to Gahrs; 4,727,889 to Niven, Jr. et al.;5,018,540 to Grubbs et al.; and 5,435,325 to Clapp et al., all of whichare incorporated by reference herein.

In certain embodiments, the tobacco pulp is subjected to supercriticalCO₂ extraction as further described herein. Generally, supercriticalfluid extraction adds supercritical CO₂ to tobacco pulp to facilitatethe removal of certain components (e.g., B[a]p and TSNA) from thetobacco pulp. The extraction can be conducted using any type ofequipment capable of bringing the tobacco into contact withsupercritical CO₂. For example, in some specific embodiments, asupercritical fluid extraction system, such as available from Jasco,Inc. (Easton, Md.) can be used. In certain embodiments, puresupercritical CO₂ is the extraction medium; however, in certainembodiments, it may be possible to use an extraction medium thatcomprises one or more components in addition to supercritical CO₂. Theextraction process may utilize a back flow medium (e.g., methanol)downstream to trap compounds that are extracted (i.e., removed) from thetobacco material.

Various parameters of the supercritical CO₂ extraction process can bevaried. In certain embodiments, altering one or more of these parameterscan alter the efficiency of the extraction process. For example, thepressure, temperature, CO₂ flow rate, and total extraction time can bevaried. For example, in certain embodiments, a pressure of about 10 MPaor greater, and more preferably a pressure of about 20 MPa or greater isused. For example, in some embodiments, a pressure of between about 5MPa and about 40 MPa (e.g., between about 10 MPa and about 40 MPa orbetween about 10 MPa and about 30 MPa) is used. In certain embodiments,a temperature of about 40° C. or greater is used, and more preferably, atemperature of about 60° C. or greater is used. For example, in someembodiments, a temperature of between about 30° C. and about 70° C. isused (e.g., between about 40° C. and about 60° C.). In certainembodiments, a flow rate of about 5 mL/min or greater is used, and morepreferably, a flow rate of about 10 mL/min or greater is used. Forexample, in some embodiments, a flow rate of between about 4 mL/min andabout 15 mL/min (e.g., between about 5 mL/min and about 10 mL/min) isused.

In certain embodiments, the total extraction time is about 10 minutes ormore, about 15 minutes or more, or about 30 minutes or more. Typically,total extraction times of about 15 minutes or more result in goodremoval of both B[a]p and TSNA (e.g., greater than about 50% removal ofboth B[a]_(p) and TSNA). In certain embodiments, total extraction timesof about 30 minutes or more provided even greater removal of both B[a]pand TSNA. It is noted that, in some embodiments, higher or lowertemperatures, higher or lower flow rates, and/or higher or lower totalextraction times can be utilized to provide good results (i.e., asignificant decrease in the concentration of B[a]p and/or TSNA).

In certain embodiments wherein the tobacco pulp treated by supercriticalCO₂ extraction has been previously subjected to an aqueous extraction,the resulting treated pulp can be characterized as a “double-extracted”tobacco pulp. A double-extracted pulp thus comprises a pulp whereinaqueous components have been removed via aqueous extraction andadditional components have been removed via supercritical CO₂extraction.

The supercritical CO₂ extraction process generally results in areduction in the amount of B[a]p and/or the amount of TSNA present inthe tobacco material. In certain embodiments, the supercritical CO₂extraction can provide a reduction in B[a]p of about 5% or more, about10% or more, about 20% or more, about 30% or more, about 40% or more,about 50% or more, about 60% or more, about 70% or more, or about 80% ormore as compared with tobacco that has not been treated by supercriticalCO₂ extraction. Generally, tobacco that has not been treated bysupercritical CO₂ extraction can have a B[a]p level that may be greaterthan about 50 ng/g, greater than about 100 ng/g, greater than about 150ng/g, or greater than about 200 ng/g. In certain embodiments, tobaccopulp that has been treated by supercritical CO₂ extraction can becharacterized as having less than about 150 ng/g, less than about 100ng/g, less than about 80 ng/g, or less than about 50 ng/g. In certainembodiments, the supercritical CO₂ extraction can provide a reduction inTSNA of about 5% or more, about 10% or more, about 20% or more, about30% or more, about 40% or more, about 50% or more, about 60% or more,about 70% or more, or about 80% or more as compared with tobacco thathas not been treated by supercritical CO₂ extraction. Generally, tobaccothat has not been treated by supercritical CO₂ extraction can have aTSNA level that may be greater than about 2,500 ng/g, greater than about5,000 ng/g, greater than about 7,500 ng/g, or greater than about 10,000ng/g. In certain embodiments, tobacco pulp that has been treated bysupercritical CO₂ extraction can be characterized as having less thanabout 5,000 ng/g, less than about 7,500 ng/g, less than about 5,000ng/g, less than about 2,000 ng/g, or less than about 1,000 ng/g.

Thereafter, a reconstituted tobacco material can be formed by adding theextract from the original extraction process back to the pre-treatedpulp (e.g., the pulp that has been treated by supercritical carbondioxide extraction). Exemplary manners and methods for providing areconstituted tobacco sheet, including casting and paper-makingtechniques, are set forth in U.S. Pat. Nos. 4,674,519 to Keritsis etal.; 4,941,484 to Clapp et al.; 4,987,906 to Young et al.; 4,972,854 toKiernan et al.; 5,099,864 to Young et al.; 5,143,097 to Sohn et al.;5,159,942 to Brinkley et al.; 5,322,076 to Brinkley et al.; 5,339,838 toYoung et al.; 5,377,698 to Litzinger et al.; 5,501,237 to Young; and6,216,707 to Kumar; each of which is incorporated herein by reference.See also the tobacco extraction and reconstituted tobacco processes setforth in U.S. Pat. Nos. 5,065,775 to Fagg and 5,360,022 to Newton etal., which are incorporated herein by reference.

The tobacco material that is subjected to the extraction process canalso be subjected to pre-treatment processes adapted to modify thesensory, chemical or physical properties of the material. For example,it may be desirable to pre-treat the tobacco material to removecomponents of the tobacco that may generate negative sensory off-notesso that those components are not extracted in the process of theinvention. Exemplary pre-treatment processes for the tobacco materialinclude fermentation, bleaching, and the like.

In some embodiments of the invention, it is advantageous to pre-treat afire-cured tobacco to change the sensory characteristics in a mannerthat can be characterized as generating a milder flavor or aroma. Oneexemplary process that can generate a milder flavor or aroma in certaintobacco materials, such as a fire-cured tobacco, is fermentation. Duringfermentation, bacteria interact with the tobacco material in a moist,temperature-controlled and pH-controlled environment to alter thechemical profile of the tobacco material. Commercially availablefermented tobacco materials could be used in the extraction process ofthe invention, such as moist snuff tobacco compositions marketed asGRIZZLY or KODIAK smokeless tobacco. Tobacco fermentation processes aredescribed, for example, in Giacomo et al., Appl. Environ. Microbiol.73(3) (2007) 825-837; U.S. Pat. No. 5,372,149 to Roth et al.; and inTobacco Production, Chemistry and Technology, Davis et al. (Eds.)(1999), all of which are incorporated by reference herein.

The tobacco extract can be utilized as a flavorful tobacco compositionthat can be incorporated into a variety of tobacco products. Inparticular, fire-cured tobacco extracts of the invention can impart thedistinctive sensory characteristics of fire-cured tobacco to varioustobacco products without introducing significant amounts of certainchemical compounds associated with unextracted or whole fire-curedtobaccos, such as BaP. The tobacco extract (e.g., the aqueous tobaccoextract) can be employed in a variety of forms. For example, the tobaccoextract can be isolated in an essentially solvent free form, such as canbe obtained as a result of the use of a spray drying or freeze dryingprocess, or other similar types of processing steps. Alternatively, theaqueous tobacco extract can be employed in a liquid faun, and as such,the content of tobacco solubles within the liquid solvent can becontrolled by selection of the amount of solvent employed forextraction, concentration of the liquid tobacco extract by removal ofsolvent, addition of solvent to dilute the liquid tobacco extract, orthe like.

The tobacco product to which the extracts of the invention are added canvary, and include any product configured or adapted to deliver tobaccoor some component thereof to the user of the product. Exemplary tobaccoproducts include smoking articles (e.g., cigarettes), smokeless tobaccoproducts, and aerosol-generating devices that contain a tobacco materialor other plant material that is not combusted during use.

Typically, the incorporation of the extract of the invention into atobacco product will involve use of a tobacco material or non-tobaccoplant material as a carrier for the extract, such as by absorbing theextract into the tobacco or other plant material or otherwiseassociating the extract with the carrier material, such as by adhesionof spray-dried particles of the extract on the carrier material. Thetypes of tobacco that can serves as the carrier for the extracts of theinvention can vary, and can include any of the tobacco types discussedherein, including various cured tobacco materials (e.g., flue-cured orair-cured tobaccos) or portions thereof (e.g., tobacco lamina or tobaccostems).

In one embodiment, the tobacco to which the extract is applied is afermented tobacco material, and the extract is applied either before,during, or after the fermentation process. The tobacco material to whichthe extract is applied will typically be characterized as having arelatively low BaP level, such as many air-cured or flue-cured tobaccomaterials or tobacco materials pre-treated to reduce BaP level. Thephysical configuration of the tobacco material to which the extract isadded can also vary, and can include tobacco materials in shredded orparticulate faun, or in the form of a sheet (e.g., reconstituted tobaccosheets) or in whole leaf form. The dry weight ratio of tobacco materialto extract of the invention can vary, but is typically about 4:1 toabout 1:4, about 2:1 to about 1:2, and often about 1.5:1 to about 1:1.5.

In one embodiment, the extract of the invention is used as a flavorfultobacco composition in the manufacture of smoking articles. For example,the extract prepared in accordance with the present invention can bemixed with casing materials and applied to tobacco as a casingingredient (e.g., using the types of methods set forth in U.S. Pat. No.4,819,668 to Shelar, which is incorporated herein by reference),incorporated into smoking articles as a top dressing ingredient, orincorporated into reconstituted tobacco materials (e.g., using the typesof tobacco reconstitution processes generally set forth in U.S. Pat.Nos. 5,143,097 to Sohn; 5,159,942 to Brinkley et al.; 5,598,868 toJakob; 5,715,844 to Young; 5,724,998 to Gellatly; and 6,216,706 toKumar, which are incorporated herein by reference). Still further, theextracts of the invention can be incorporated into a cigarette filter(e.g., in the filter plug, plug wrap, or tipping paper) or incorporatedinto cigarette wrapping paper, preferably on the inside surface, duringthe cigarette manufacturing process.

Referring to FIG. 1, there is shown a smoking article 10 in the form ofa cigarette and possessing certain representative components of asmoking article that can contain the extract of the present invention.The cigarette 10 includes a generally cylindrical rod 12 of a charge orroll of smokable filler material (e.g., about 0.3 to about 1.0 g ofsmokable filler material such as tobacco material) contained in acircumscribing wrapping material 16. The rod 12 is conventionallyreferred to as a “tobacco rod.” The ends of the tobacco rod 12 are opento expose the smokable filler material. The cigarette 10 is shown ashaving one optional band 22 (e.g., a printed coating including afilm-forming agent, such as starch, ethylcellulose, or sodium alginate)applied to the wrapping material 16, and that band circumscribes thecigarette rod in a direction transverse to the longitudinal axis of thecigarette. The band 22 can be printed on the inner surface of thewrapping material (i.e., facing the smokable filler material), or lesspreferably, on the outer surface of the wrapping material.

At one end of the tobacco rod 12 is the lighting end 18, and at themouth end 20 is positioned a filter element 26. The filter element 26positioned adjacent one end of the tobacco rod 12 such that the filterelement and tobacco rod are axially aligned in an end-to-endrelationship, preferably abutting one another. Filter element 26 mayhave a generally cylindrical shape, and the diameter thereof may beessentially equal to the diameter of the tobacco rod. The ends of thefilter element 26 permit the passage of air and smoke therethrough.

A ventilated or air diluted smoking article can be provided with anoptional air dilution means, such as a series of perforations 30, eachof which extend through the tipping material and plug wrap. The optionalperforations 30 can be made by various techniques known to those ofordinary skill in the art, such as laser perforation techniques.Alternatively, so-called off-line air dilution techniques can be used(e.g., through the use of porous paper plug wrap and pre-perforatedtipping paper).

The extracts of the invention can also be incorporated intoaerosol-generating devices that contain tobacco material (or someportion or component thereof) that is not intended to be combustedduring use. Exemplary references that describe smoking articles of atype that generate flavored vapor, visible aerosol, or a mixture offlavored vapor and visible aerosol, include U.S. Pat. Nos. 3,258,015 toEllis et al.; 3,356,094 to Ellis et al.; 3,516,417 to Moses; 4,347,855to Lanzellotti et al.; 4,340,072 to Bolt et al.; 4,391,285 to Burnett etal.; 4,917,121 to Riehl et al.; 4,924,886 to Litzinger; and 5,060,676 toHearn et al., all of which are incorporated by reference herein. Many ofthese types of smoking articles employ a combustible fuel source that isburned to provide an aerosol and/or to heat an aerosol-forming material.See, for example, U.S. Pat. Nos. 4,756,318 to Clearman et al.; 4,714,082to Banerjee et al.; 4,771,795 to White et al.; 4,793,365 to Sensabaughet al.; 4,917,128 to Clearman et al.; 4,961,438 to Korte; 4,966,171 toSerrano et al.; 4,969,476 to Bale et al.; 4,991,606 to Serrano et al.;5,020,548 to Farrier et al.; 5,033,483 to Clearman et al.; 5,040,551 toSchlatter et al.; 5,050,621 to Creighton et al.; 5,065,776 to Lawson;5,076,296 to Nystrom et al.; 5,076,297 to Farrier et al.; 5,099,861 toClearman et al.; 5,105,835 to Drewett et al.; 5,105,837 to Barnes etal.; 5,115,820 to Hauser et al.; 5,148,821 to Best et al.; 5,159,940 toHayward et al.; 5,178,167 to Riggs et al.; 5,183,062 to Clearman et al.;5,211,684 to Shannon et al.; 5,240,014 to Deevi et al.; 5,240,016 toNichols et al.; 5,345,955 to Clearman et al.; 5,551,451 to Riggs et al.;5,595,577 to Bensalem et al.; 5,819,751 to Barnes et al.; 6,089,857 toMatsuura et al.; 6,095,152 to Beven et al; 6,578,584 to Beven; and6,730,832 to Dominguez; which are incorporated herein by reference.Furthermore, certain types of cigarettes that employ carbonaceous fuelelements have been commercially marketed under the brand names “Premier”and “Eclipse” by R. J. Reynolds Tobacco Company. See, for example, thosetypes of cigarettes described in Chemical and Biological Studies on NewCigarette Prototypes that Heat Instead of Burn Tobacco, R. J. ReynoldsTobacco Company Monograph (1988) and Inhalation Toxicology, 12:5, p.1-58 (2000). Addition types of aerosol-generating devices are describedin U.S. Pat. No. 7,726,320 to Robinson et al. and US Pat. Appl. Pub.Nos. 2006/0196518 and 2007/0267031, both to Hon, all of which areincorporated by reference herein.

The extracts of the invention can be incorporated into smokeless tobaccoproducts, such as loose moist snuff (e.g., snus), loose dry snuff,chewing tobacco, pelletized tobacco pieces (e.g., having the shapes ofpills, tablets, spheres, coins, beads, obloids or beans), extruded orformed tobacco strips, pieces, rods, cylinders or sticks, finely dividedground powders, finely divided or milled agglomerates of powdered piecesand components, flake-like pieces, molded processed tobacco pieces,pieces of tobacco-containing gum, rolls of tape-like films, readilywater-dissolvable or water-dispersible films or strips (e.g., US Pat.App. Pub. No. 2006/0198873 to Chan et al.), or capsule-like materialspossessing an outer shell (e.g., a pliable or hard outer shell that canbe clear, colorless, translucent or highly colored in nature) and aninner region possessing tobacco or tobacco flavor (e.g., a Newtonianfluid or a thixotropic fluid incorporating tobacco of some form).Various types of smokeless tobacco products are set forth in U.S. Pat.Nos. 1,376,586 to Schwartz; 3,696,917 to Levi; 4,513,756 to Pittman etal.; 4,528,993 to Sensabaugh, Jr. et al.; 4,624,269 to Story et al.;4,987,907 to Townsend; 5,092,352 to Sprinkle, I I I et al.; and5,387,416 to White et al.; US Pat. App. Pub. Nos. 2005/0244521 toStrickland et al. and 2008/0196730 to Engstrom et al.; PCT WO 04/095959to Arnarp et al.; PCT WO 05/063060 to Atchley et al.; PCT WO 05/016036to Bjorkholm; and PCT WO 05/041699 to Quinter et al., each of which isincorporated herein by reference. See also, the types of smokelesstobacco formulations, ingredients, and processing methodologies setforth in U.S. Pat. Nos. 6,953,040 to Atchley et al. and 7,032,601 toAtchley et al.; US Pat. Appl. Pub. Nos. 2002/0162562 to Williams;2002/0162563 to Williams; 2003/0070687 to Atchley et al.; 2004/0020503to Williams, 2005/0178398 to Breslin et al.; 2006/0191548 to Stricklandet al.; 2007/0062549 to Holton, Jr. et al.; 2007/0186941 to Holton, Jr.et al.; 2007/0186942 to Strickland et al.; 2008/0029110 to Dube et al.;2008/0029116 to Robinson et al.; 2008/0029117 to Mua et al.;2008/0173317 to Robinson et al.; 2008/0209586 to Neilsen et al.;2010/0018541 to Gerardi et al.; 2010/0018540 to Doolittle et al.; and2010/0116281 to Marshall et al., each of which is incorporated herein byreference.

Referring to FIG. 2, a representative snus type of tobacco productcomprising the extract of the present invention is shown. In particular,FIG. 2 illustrates a smokeless tobacco product 40 having awater-permeable outer pouch 42 containing a smokeless tobaccocomposition 44, wherein the tobacco composition includes a shredded orparticulate tobacco material serving as a carrier for the extract of theinvention.

Many exemplary smokeless tobacco compositions that can benefit from useof the extract of the invention comprise shredded or particulate tobaccomaterial that can serve as a carrier for the flavorful extract of theinvention. The smokeless tobacco compositions of the invention can alsoinclude a water-soluble polymeric binder material and optionally otheringredients that provide a dissolvable composition that will slowlydisintegrate in the oral cavity during use. In certain embodiments, thesmokeless tobacco composition can include lipid components that providea meltable composition that melts (as opposed to merely dissolving) inthe oral cavity, such as compositions set forth in U.S. application Ser.No. 12/854,342 to Cantrell et al., filed Aug. 11, 2010, and which isincorporated by reference herein.

In one particular smokeless tobacco product embodiment, the extract ofthe invention is added to a non-tobacco plant material, such as a plantmaterial selected from potato, beet (e.g., sugar beet), grain, pea,apple, and the like. The non-tobacco plant material can be used in aprocessed faun. In certain preferred embodiments, the non-tobacco plantmaterial can be used in an extracted form, and as such, at least aportion of certain solvent soluble components are removed from thatmaterial. The non-tobacco extracted plant material is typically highlyextracted, meaning a substantial amount of the aqueous soluble portionof the plant material has been removed. For example, a water-extractedpulp can be obtained by extracting significant amounts of water solublecomponents from the plant material. For example, certain water-extractedplant materials can comprise less than about 20 weight percent, andoften less than about 10 weight percent water soluble components; anddepending upon processing conditions, certain water-extracted plantmaterials can be virtually free of water soluble components (e.g., lessthan about 1 weight percent water soluble components). One preferredwater-extracted plant material is water extracted sugar beet pulp (e.g.,water extracted sugar beet leaf pulp). The extracted non-tobacco plantmaterial is typically used in a form that can be described as shredded,ground, granulated, fine particulate, or powder form. The dry weightratio of non-tobacco plant material to tobacco extract of the inventionis typically about 4:1 to about 1:4, about 2:1 to about 1:2, and oftenabout 1.5:1 to about 1:1.5. Smokeless tobacco products of this type areset forth in U.S. application Ser. No. 12/756,656 to Beeson et al, filedApr. 8, 2010, which is incorporated by reference herein.

Further additives can be admixed with, or otherwise incorporated within,the smokeless tobacco compositions according to the invention. Theadditives can be artificial, or can be obtained or derived from herbalor biological sources. Exemplary types of additives include salts (e.g.,sodium chloride, potassium chloride, sodium citrate, potassium citrate,sodium acetate, potassium acetate, and the like), natural sweeteners(e.g., fructose, sucrose, glucose, maltose, vanillin, ethylvanillinglucoside, mannose, galactose, lactose, and the like), artificialsweeteners (e.g., sucralose, saccharin, aspartame, acesulfame K, neotameand the like), organic and inorganic fillers (e.g., grains, processedgrains, puffed grains, maltodextrin, dextrose, calcium carbonate,calcium phosphate, corn starch, lactose, manitol, xylitol, sorbitol,finely divided cellulose, and the like), binders (e.g., povidone, sodiumcarboxymethylcellulose and other modified cellulosic types of binders,sodium alginate, xanthan gum, starch-based binders, gum arabic,lecithin, and the like), pH adjusters or buffering agents (e.g., metalhydroxides, preferably alkali metal hydroxides such as sodium hydroxideand potassium hydroxide, and other alkali metal buffers such as metalcarbonates, preferably potassium carbonate or sodium carbonate, or metalbicarbonates such as sodium bicarbonate, and the like), colorants (e.g.,dyes and pigments, including caramel coloring and titanium dioxide, andthe like), humectants (e.g., glycerin, propylene glycol, and the like),oral care additives (e.g., thyme oil, eucalyptus oil, and zinc),preservatives (e.g., potassium sorbate, and the like), syrups (e.g.,honey, high fructose corn syrup, and the like), disintegration aids(e.g., microcrystalline cellulose, croscarmellose sodium, crospovidone,sodium starch glycolate, pregelatinized corn starch, and the like),flavorant and flavoring mixtures, antioxidants, and mixtures thereof. Ifdesired, the additive can be microencapsulated as set forth in US PatentAppl. Pub. No. 2008/0029110 to Dube et al., which is incorporated byreference herein.

The amount of tobacco extract that is added to a tobacco composition ortobacco product can vary, and will depend in part on the desiredfunction of the extract, the chemical makeup of the extract, and thetype of tobacco composition or product to which the extract is added.Unless otherwise indicated herein, the amount added to a tobacco productwill typically not exceed about 25 weight percent based on the total dryweight of the tobacco composition to which the extract is added. Whenthe extract is employed within a smoking article, the amount of extractwill typically be at least about 5 ppm, generally at least about 10 ppm,and often at least about 100 ppm, based on the total dry weight of thetobacco material within the smoking article; but will typically be lessthan about 5 percent, generally less than about 2 percent, and oftenless than about 1 percent, based on the total dry weight of the tobaccomaterial within the smoking article. When the extract is employed withina smokeless tobacco product, the amount of extract will typically be atleast about 5 ppm, generally at least about 10 ppm, and often at leastabout 100 ppm, based on the total dry weight of the tobacco materialwithin the smokeless tobacco product; but will typically be less thanabout 10 percent, generally less than about 5 percent, and often lessthan about 1 percent, based on the total dry weight of the tobaccomaterial within the smokeless tobacco product.

EXPERIMENTAL

Aspects of the present invention are more fully illustrated by thefollowing examples, which are set forth to illustrate certain aspects ofthe present invention and are not to be construed as limiting thereof.Unless otherwise noted, all parts and percentages are by weight.

Example 1

A fire-cured tobacco is extracted using water. A typical extractionprocess combines milled tobacco (e.g., 100% pass 0.250 inch screen) withwater at a ratio of 8 parts water to 1 part tobacco at a temperature ofabout 72° C. The mixture is agitated for one hour and the suspendedsolids removed by filtration using a 5 micron filter bag. The resultingtobacco extract retains the aroma and sensory characteristics of thefire-cured tobacco. The original fire-cured tobacco has a BaP levelprior to extraction of about 150 to 800 parts per billion and theseparated liquid extract has a BaP level of less than about 1 part perbillion.

Example 2

An air-cured tobacco is subjected to the same extraction process as setforth in Example 1. The original air-cured tobacco has a BaP level priorto extraction of about 10-150 parts per billion and the separated liquidextract has a BaP level of less than about 1 part per billion.

Example 3

Ground fire-cured tobacco having a moisture content of 10% is extractedusing supercritical CO₂. An exemplary extraction process employs a Jascosupercritical fluid extraction system, comprising preparation pumps,column thermostat, photodiode array detector, HPLC pump, automatic backpressure regulator, and 6-valve change unit capable of collectingsamples in a time sequence manner during a single extraction run. Astainless steel pressure extraction vessel is located inside the columnthermostat, with a pressure limit of 40 MPa. The extractions areconducted using 100% CO₂ and methanol is used as the back flow to trapextracted compounds.

The pressure, temperature, and CO₂ flow rate with which the extractionis conducted are varied to assess the effects of each on the removal ofB[a]p and TSNA from the tobacco. Pressure is held at 10, 20, or 30 MPa,temperature is held at either 40° C. or 60° C., and CO₂ flow rate is setat 5 or 10 mL/min. The resulting solid residues are extracted withhexanes and subjected to liquid chromatography to evaluate B[a]p andTSNA concentrations of the extracted material as compared with those ofunextracted tobacco.

At higher temperatures and lower pressures, only a small decrease inB[a]p (˜5% reduction) and TSNA (less than about 20% reduction) areobserved. Increasing the pressure at which the extraction is conductedprovides comparable results. The highest TSNA reduction is obtainedusing moderate (20 MPa) pressure, a temperature of 60° C., and a flowrate of 10 mL/min. The highest B[a]p reduction (62% reduction) isobtained using a pressure of 30 MPa, a temperature of 60° C., and a flowrate of 10 mL/min.

Example 4

Water-extracted fire cured tobacco pulp having a moisture content of 11%is extracted using supercritical CO₂ using the method described inExample 3. The CO₂ flow rate is set at 10 mL/min and the temperature isset at 40° C. or 60° C. and pressure is set at 10, 20, or 30 MPa toevaluate the effect of temperature and pressure on the removal of B[a]pand TSNA from water-extracted fire-cured tobacco.

As temperature and pressure are increased, more B[a]p and TSNA areremoved from the tobacco. However, at a pressure of 10 MPa, increasingthe temperature from 40° C. to 60° C. does not have much of an effect onthe removal of B[a]p or TSNA from water-extracted fire-cured tobacco.The highest TSNA reduction (63%) is obtained using a pressure of 30 MPa,and a temperature of 60° C. The highest B[a]p reduction (46% and 47%,respectively) is obtained using a pressure of 30 MPa with a temperatureof either 40° C. or 60° C.

Example 5

Ground fire-cured tobacco with a moisture content of 10% is extractedusing supercritical CO₂ as described in Example 3. The pressure is heldat 20 MPa, the temperature is held at 40° C., and the flow rate is heldat 10 mL/min CO₂. The extraction time is varied to assess the effect ofextraction time on the removal of B[a]p and TSNA. Extractions areconducted over periods of 15 minutes, 30 minutes, 45 minutes, 60minutes, and 120 minutes. The decrease in B[a]p and TSNA observed withthe sample that was subjected to extraction for 30 minutes is comparableto that observed with samples subjected to extraction for longer than 30minutes; therefore, 30 minutes is selected as the extraction durationfor remaining experiments.

Water-extracted fire-cured tobacco pulp with a moisture content of 11%is similarly extracted using various extraction times. Again, anextraction time of 30 minutes results in sufficient removal of bothB[a]p and TSNA.

Example 6

Various fire-cured and water-extracted fire cured tobacco pulp samplesare extracted using supercritical CO₂ as described in Example 3. Themoisture content of the tobacco samples prior to extraction is varied toevaluate the effect of moisture on the removal of B[a]p and TSNA. Thepressure is held at 20 MPa, the temperature is held at 40° C., the flowrate is 10 mL/min CO₂, and the run time is 30 minutes. Varying levels ofmoisture are added to tobacco samples prior to extraction, to givefire-cured tobacco samples having 10%, 16%, 21%, 25%, and 31% moisturecontent and water-extracted fire-cured tobacco samples having 10%, 11%,16%, 21%, and 27% moisture content. The actual amounts of tobaccosamples charged into the extraction vessels are calculated based onmoisture content to achieve the same amount (10 g) of oven-dried weightsuch that each sample subjected to the extraction initially contains thesame overall amount of tobacco. Each sample is extracted and theresulting solid residues are air-dried for at least 4 days to bring themoisture content of each sample residue to relatively the same level.

For the fire-cured tobacco, increasing the moisture content from 10% to31% results in greater TSNA reduction (from 60% TSNA reduction at 10%moisture content to 80% TSNA reduction at 31% moisture content) andgreater B[a]p reduction (from 45% B[a]p reduction at 10% moisturecontent to 80% B[a]p reduction at 31% moisture content).

For the water-extracted fire-cured tobacco, increasing the moisturecontent from 10% to 27% similarly results in a greater TSNA reduction(45% TSNA reduction at 10% moisture content to 80% TSNA reduction at 27%moisture content) and a greater B[a]p reduction (20% B[a]p reduction at10% moisture content to 50% B[a]p reduction at 27% moisture content).

Seemingly, introduction of moisture to the tobacco material facilitatesthe removal of both B[a]p and TSNA. Although not intended to be limitingof the invention, one explanation is that the addition of water may openthe internal structure of the tobacco, leaving it more accessible forextraction. One other explanation is that, because B[a]p is non-polar,the presence of more water in the tobacco more effectively “pushes” theB[a]p out of the tobacco. TSNA has both polar and non-polar features andthus, this theory may explain the increase in both B[a]_(p) and TSNAremoval as the moisture level of the tobacco is increased.

Example 7

Various fire-cured and water-extracted fire cured tobacco pulp samplesare extracted using supercritical CO₂ as described in Example 3. Varyingamounts of ethanol are added to act as a modifier for the supercriticalCO₂ to evaluate the effect of ethanol on the removal of B[a]_(p) andTSNA. Temperature and pressure are also varied to evaluate the effect ofthese parameters with the addition of ethanol to the extraction system.The pressure is held at 10 or 20 MPa, the temperature is held at 40° C.or 60° C., the flow rate is 10 mL/min CO₂, and the run time is 30minutes. Varying amounts of ethanol are added to the CO₂ used to conductextraction of the tobacco samples. Specifically, the extraction mediaevaluated are: 100% CO₂, CO₂ with 10% ethanol by weight, and CO₂ with30% ethanol by volume. Extractions of both water-extracted andfire-cured tobacco and fire-cured tobacco are conducted with each ofthese extraction media. Extractions are conducted at temperatures of 40°C. and 60° C. and at pressures of 10 MPa and 20 MPa with each extractionmedium. Each sample is extracted and the resulting solid residues areevaluated to determine the reduction in B [a]p and TSNA. For both thefire-cured tobacco and the water-extracted fire-cured tobacco, addingethanol results in a greater reduction in both B[a]p and TSNA under alltemperature and pressure conditions evaluated.

For example, at 60° C. and 10 MPa, extraction of water-extractedfire-cured tobacco with CO₂ alone results in a 20% reduction in B[a]pand a 32% reduction in TSNA, whereas extraction with 30% ethanol in CO₂results in a 71% reduction in B[a]p and a 79% reduction in TSNA. Underthe same conditions, extraction of fire-cured tobacco with CO₂ aloneresults in a 37% reduction in B[a]p and a 46% reduction in TSNA, whereasextraction with 30% ethanol in CO₂ results in an 80% reduction in B[a]pand a 75% reduction in TSNA.

The highest level of B[a]p reduction (74%) in water-extracted fire-curedtobacco in this example is achieved with an extraction medium of 30%ethanol in CO₂ at a temperature of 60° C. and a pressure of 20 MPa. Thehighest level of TSNA reduction (79%) in water-extracted fire-curedtobacco in this example is achieved with an extraction medium of 30%ethanol in CO₂ at a temperature of 60° C. and a pressure of either 10 or20 MPa.

The highest level of B[a]p reduction (80%) in fire-cured tobacco in thisexample is achieved with an extraction medium of 30% ethanol in CO₂ at atemperature of 60° C. and a pressure of 10 MPa. The highest level ofTSNA reduction (75%) in fire-cured tobacco in this example is achievedwith an extraction medium of 30% ethanol in CO₂ at a temperature of 60°C. and a pressure of 10 MPa.

Generally, adding ethanol up to about 30% by volume to CO₂ for use asthe extraction medium increases the removal of both B[a]P and TSNA.Varying the temperature of such extractions from 40° C. to 60° C. haslittle effect, although in certain cases, it can result in slightlyenhanced B[a]P and TSNA removal. Similarly, increasing the pressure ofsuch extractions from 10 MPa to 20 MPa has little effect, although incertain cases, it can result in slightly enhanced B[a]P and TSNAremoval.

Many modifications and other embodiments of the invention will come tomind to one skilled in the art to which this invention pertains havingthe benefit of the teachings presented in the foregoing description.Therefore, it is to be understood that the invention is not to belimited to the specific embodiments disclosed and that modifications andother embodiments are intended to be included within the scope of theappended claims. Although specific terms are employed herein, they areused in a generic and descriptive sense only and not for purposes oflimitation.

1. A method of producing a tobacco composition for use in a tobaccoproduct, the tobacco composition characterized by a reducedbenzo[a]pyrene concentration, comprising: mixing an extracted pulp of acured tobacco material having a first benzo[a]pyrene concentration withsupercritical carbon dioxide to provide intimate contact between theextracted pulp and the supercritical carbon dioxide; maintaining theintimate contact for a time and at a temperature sufficient to form atreated tobacco pulp exhibiting a second benzo[a]pyrene concentrationlower than the first benzo[a]pyrene concentration; and separating thetreated tobacco pulp from a residual supercritical carbon dioxideextract comprising components of the tobacco material that are solublein the supercritical carbon dioxide.
 2. The method of claim 1, whereinthe cured tobacco material of the extracted pulp comprises groundfire-cured tobacco.
 3. The method of claim 2, wherein the extracted pulpis an aqueous extracted tobacco material.
 4. The method of claim 1,wherein the pressure at which the mixing is conducted is about 10 MPa orgreater.
 5. The method of claim 1, wherein the pressure at which themixing is conducted is about 20 MPa or greater.
 6. The method of claim1, wherein the pressure at which the mixing is conducted is betweenabout 10 MPa and about 40 MPa.
 7. The method of claim 1, wherein thetemperature at which the mixing is conducted is about 40° C. or greater.8. The method of claim 1, wherein the temperature at which the mixing isconducted is about 50° C. or greater.
 9. The method of claim 1, whereinthe temperature at which the mixing is conducted is between about 40° C.and about 60° C.
 10. The method of claim 1, wherein the mixing isconducted for a period of at least about 15 minutes.
 11. The method ofclaim 1, wherein the mixing is conducted for a period of at least about30 minutes.
 12. The method of claim 1, wherein the mixing step comprisesmixing the extracted pulp with supercritical carbon dioxide and ethanol.13. The method of claim 12, wherein the ethanol is present in an amountof about 10% to about 30% by volume of the supercritical carbon dioxideand ethanol.
 14. The method of claim 1, wherein the first benzo[a]pyreneconcentration is at least about 200 ng/g and the second benzo[a]pyreneconcentration is less than about 80 ng/g.
 15. The method of claim 1,wherein the TSNA concentration of the treated tobacco pulp is less thanthat of the extracted pulp of cured tobacco material.
 16. The method ofclaim 15, wherein the extracted pulp of cured tobacco material has aTSNA concentration of greater than about 5,000 ng/g and the treatedtobacco pulp has a TSNA concentration of less than about 2,000 ng/g. 17.The method of claim 1, further comprising adding a tobacco extract tothe treated tobacco pulp to form a tobacco composition.
 18. The methodof claim 17, wherein the tobacco extract is an aqueous extract.
 19. Themethod of claim 17, wherein the tobacco extract and the treated tobaccopulp are derived from the same tobacco sample.
 20. The method of claim1, further comprising introducing the treated tobacco pulp into atobacco product.
 21. The method of claim 20, wherein the tobacco productis selected from the group consisting of smoking articles, smokelesstobacco products, and aerosol-generating devices configured fornon-combustion of plant material.
 22. The method of claim 20, whereinthe tobacco product is a smokeless tobacco composition selected from thegroup consisting of moist snuff, dry snuff, chewing tobacco,tobacco-containing gums, and dissolvable or meltable tobacco products.23. A tobacco product comprising an extracted pulp of a cured tobaccomaterial, wherein the extracted pulp of cured tobacco material ischaracterized as having a B[a]p concentration of less than about 80ng/g.
 24. The tobacco product of claim 23, wherein the extracted pulp ischaracterized as having a TSNA concentration of less than about 2,000ng/g.
 25. The tobacco product of claim 23, further comprising a tobaccoextract carried by the extracted pulp.
 26. The tobacco product of claim25, wherein the tobacco extract is an aqueous extract.
 27. The tobaccoproduct of claim 23, wherein the tobacco extract and the extracted pulpof cured tobacco material are derived from the same tobacco sample. 28.The tobacco product of claim 23, wherein the tobacco product is in theform of a smokeless tobacco composition, a smoking article, or anaerosol-generating device configured for non-combustion of plantmaterial.
 29. The tobacco product of claim 28, wherein the tobaccoproduct is in the form of a smokeless tobacco composition selected fromthe group consisting of moist snuff, dry snuff, chewing tobacco,tobacco-containing gums, and dissolvable or meltable tobacco products.